void main(List<String> args) {
  //1. Number 与 String类型之间的转换
  // Number类型转换成String类型 toString()

  //String类型转成Number类型 parse

  String str = '123';
  var myNum = int.parse(str);
  print(myNum);
  print(myNum is int);

  try {
    String price = "123";
    var mNum = double.parse(price);
    print(mNum);
  } catch (err) {
    print(err);
  }
  int mNum2 = 1234;
  String str2 = mNum2.toString();
  print(str2);
}
